Hi all, I wonder if we have a ETA for this change? thanks
On Wed, Jan 31, 2024 at 10:30 AM Chertara, Rahil
<rcher...@amazon.com.invalid> wrote:
> Sure, I can look into adding this to the spec.
> Thanks to everyone for sharing their thoughts, appreciate it!
>
>
>
> *From: *Ryan Blue <b...@tabular.io>
> *Reply-To: *"dev@iceberg.apache.org" <dev@iceberg.apache.org>
> *Date: *Wednesday, January 31, 2024 at 10:22 AM
> *To: *"dev@iceberg.apache.org" <dev@iceberg.apache.org>
> *Subject: *RE: [EXTERNAL] Proposal for REST APIs for Iceberg table scans
>
>
>
> *CAUTION*: This email originated from outside of the organization. Do not
> click links or open attachments unless you can confirm the sender and know
> the content is safe.
>
>
>
> Looks good to me! Should we get a PR up to add it to the OpenAPI spec?
>
>
>
> On Wed, Jan 31, 2024 at 10:16 AM Jack Ye <yezhao...@gmail.com> wrote:
>
> Sounds good. I don't really have any strong opinions here. So looks like
> we are landing on this?
>
>
>
>
> *PreplanTable: POST /v1/namespaces/ns/tables/t/preplan *{ "filter": {
> "type": "in", "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"] }
>
> { "plan-tasks": [ { ... }, { ... } ] } // opaque object
>
>
> *PlanTable w/o a plan task: POST /v1/namespaces/ns/tables/t/plan *{
> "filter": {"type": "in", "term": "x", "values": [1, 2, 3] }, "select":
> ["x", "a.b"] }
>
>
> { "file-scan-tasks": [ { ... }, { ... } ] } // FileScanTask OpenAPI model
>
>
>
> *PlanTable w/ a plan task: POST /v1/namespaces/ns/tables/t/plan *{
> "filter": {"type": "in", "term": "x", "values": [1, 2, 3] }, "select":
> ["x", "a.b"], "plan-task": { ... } }
>
> { "file-scan-tasks": [ { ... }, { ... } ] }
>
>
>
> -Jack
>
>
>
> On Wed, Jan 31, 2024 at 10:08 AM Ryan Blue <b...@tabular.io> wrote:
>
> I agree with Dan. I'd rather have two endpoints instead of needing an
> option that changes the behavior entirely in the same route. I don't think
> that a `preplan` route would be too bad.
>
>
>
> On Wed, Jan 31, 2024 at 9:51 AM Daniel Weeks <dwe...@apache.org> wrote:
>
> I agree with the opaque tokens.
>
>
>
> However, I'm concerned we're overloading the endpoint two perform two
> distinctly different operations: distribute a plan and scan a plan.
>
>
>
> Changing the task-type then changes the behavior and the result. I feel
> it would be more straightforward to separate the distribute and scan
> endpoints. Then clients can call the scan directly if they do not know how
> to distribute and the behavior is clear from the REST Specification.
>
>
>
> -Dan
>
>
>
> On Tue, Jan 30, 2024 at 9:09 PM Jack Ye <yezhao...@gmail.com> wrote:
>
> +1 for having the opaque plan tasks, that's probably the most flexible way
> forward. And let's call them *plan tasks* going forward to standardize
> the terminology.
>
>
>
> I think the name of the APIs can be determined based on the actual API
> shape. For example, if we centralize these 2 plan and pre-plan actions to a
> single API endpoint but just requesting different task types:
>
>
>
>
> *pre-plan: POST /v1/namespaces/ns/tables/t/plan *{ "filter": { "type":
> "in", "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"],
> "task-type": "plan-task" }
>
> { "plan-tasks": [ { ... }, { ... } ] }
>
>
> *plan without a plan-task: POST /v1/namespaces/ns/tables/t/plan *{
> "filter": {"type": "in", "term": "x", "values": [1, 2, 3] }, "select":
> ["x", "a.b"], "task-type": "file-scan-task" } // file-scan-task should be
> the default type
>
>
> { "file-scan-tasks": [ { ... }, { ... } ] }
>
>
>
> *plan with a plan-task: POST /v1/namespaces/ns/tables/t/plan *{ "filter":
> {"type": "in", "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"],
> "task-type": "file-scan-task", "plan-task": { ... } }
>
> { "file-scan-tasks": [...] }
>
>
>
> In this model, we just have a single API, and we can call it something
> like PlanTable or PlanTableScan.
>
>
>
> What do you think?
>
>
>
> -Jack
>
>
>
>
>
> On Mon, Jan 29, 2024 at 6:17 PM Renjie Liu <liurenjie2...@gmail.com>
> wrote:
>
> But to move forward, I think we should go with the option that preserves
> flexibility. I think the spec should state that plan tasks (if we call them
> that) are a JSON object that should be sent as-is back to the REST service
> to be used.
>
>
>
> +1 for this.
>
>
>
> > One more thing that I would also change is that I don't think the "plan"
> and "scan" endpoints make much sense. We refer to the "scan" portion of
> this as "planFiles" in the reference implementation, and "scan" is used for
> actually reading data. To be less confusing, I think that file scan tasks
> should be returned by a "plan" endpoint and the manifest plan tasks (or
> shards) should be returned by a "pre-plan" endpoint. Does anyone else like
> the names "pre-plan" and "plan" better?
>
>
>
> I agree that "scan" may be quite confusing since it's actually planning
> file scan. Another options I can provide is: "plan" -> "plan-table-scan",
> "scan" -> "plan-file-scan"
>
>
>
>
>
>
>
>
>
> On Tue, Jan 30, 2024 at 9:03 AM Ryan Blue <b...@tabular.io> wrote:
>
> As you noted the main point we still need to decide on is whether to have
> a standard "shard" definition (e.g. manifest plan task) or to allow it to
> be opaque and specific to catalogs implementing the protocol. I've not
> replied because I keep coming back to this decision and I'm not sure
> whether the advantage is being clear about how it works (being explicit) or
> allowing implementations to differ (opaque). I'm skeptical that there will
> be other strategies.
>
>
>
> But to move forward, I think we should go with the option that preserves
> flexibility. I think the spec should state that plan tasks (if we call them
> that) are a JSON object that should be sent as-is back to the REST service
> to be used.
>
>
>
> One more thing that I would also change is that I don't think the "plan"
> and "scan" endpoints make much sense. We refer to the "scan" portion of
> this as "planFiles" in the reference implementation, and "scan" is used for
> actually reading data. To be less confusing, I think that file scan tasks
> should be returned by a "plan" endpoint and the manifest plan tasks (or
> shards) should be returned by a "pre-plan" endpoint. Does anyone else like
> the names "pre-plan" and "plan" better?
>
>
>
> Ryan
>
>
>
> On Mon, Jan 29, 2024 at 12:02 PM Chertara, Rahil
> <rcher...@amazon.com.invalid> wrote:
>
> Hi All hope everyone is doing well,
>
>
> Wanted to revive the discussion around the Rest Table Scan API work. For a
> refresher here is the original proposal:
> https://docs.google.com/document/d/1FdjCnFZM1fNtgyb9-v9fU4FwOX4An-pqEwSaJe8RgUg/edit#heading=h.cftjlkb2wh4h
> as well as the PR: https://github.com/apache/iceberg/pull/9252
>
>
> From the last messages on the thread, I believe Ryan and Jack were in
> favor of having two distinct api endpoints /plan and /scan, as well as a
> stricter json definition for the "shard”, here is an example below from
> what was discussed.
>
>
> *POST /v1/namespaces/ns/tables/t/plan *{ "filter": { "type": "in",
> "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"]}
>
> { "manifest-plan-tasks": [
> { "start": 0, "length": 1000, "manifest": { "path":
> "s3://some/manifest.avro", ...}, "delete-manifests": [...] },
> { ... }
> ]}
>
>
> *POST /v1/namespaces/ns/tables/t/scan *{ "filter": {"type": "in", "term":
> "x", "values": [1, 2, 3] },
>
> "select": ["x", "a.b"],
> "manifest-plan-task": { "start": 0, "length": 1000, "manifest": {
> "path": "s3://some/manifest.avro", ...}, "delete-manifests": [...] } }
>
> { "file-scan-tasks": [...] }
>
>
> *POST /v1/namespaces/ns/tables/t/scan *{ "filter": {"type": "in", "term":
> "x", "values": [1, 2, 3] }, "select": ["x", "a.b"]}
>
>
> { "file-scan-tasks": [...] }
>
>
>
> However IIRC Micah and Renjie had some concerns around this stricter
> structure as this can make it harder to evolve in the future, as well as
> some potential scalability challenges for larger tables that have many
> manifest files. (Feel free to expand further on the concerns if my
> understanding is incorrect).
>
>
>
> Would appreciate if the community can leave any more thoughts/feedback on
> this thread, as well as on the google doc, and the PR.
>
>
>
> Regards,
> Rahil Chertara
>
>
>
> *From: *Renjie Liu <liurenjie2...@gmail.com>
> *Reply-To: *"dev@iceberg.apache.org" <dev@iceberg.apache.org>
> *Date: *Thursday, December 21, 2023 at 10:35 PM
> *To: *"dev@iceberg.apache.org" <dev@iceberg.apache.org>
> *Subject: *RE: [EXTERNAL] Proposal for REST APIs for Iceberg table scans
>
>
>
> *CAUTION*: This email originated from outside of the organization. Do not
> click links or open attachments unless you can confirm the sender and know
> the content is safe.
>
>
>
> I share the same concern with Micah. The shard detail should be
> implementation details of the server, rather than exposing directly to the
> client. If the goal is to make things stateless, we just need to attach a
> snapshot id + shard id, then a determined algorithm is supposed to give the
> same result. Also another concern is for huge analytics tables, we may have
> a lot of manifest files, which may lead to large traffic from the rest
> server.
>
>
>
> On Thu, Dec 21, 2023 at 7:41 AM Micah Kornfield <emkornfi...@gmail.com>
> wrote:
>
> Also +1 for having a more strict definition of the shard. Having arbitrary
> JSON was basically what we experimented with a string shard ID, and we
> ended up with something very similar to the manifest plan task you describe
> in the serialized ID string.
>
>
>
> IIUC the proposal correctly, I'd actually be -0.0 on the stricter
> structure. I think forcing a contract where it isn't strictly necessary
> makes it harder to evolve the system in the future. For example it makes
> it harder to address potential scalability problems in a transparent way
> (e.g. extreme edge cases in cardinality between manifest files and delete
> files).
>
>
>
> It also seems like it might overly constrain implementations (it is not
> clear we should need to compute the mapping between delete file manifests
> to data file manifests up front to start planning).
>
>
>
> On Tue, Dec 19, 2023 at 2:10 PM Jack Ye <yezhao...@gmail.com> wrote:
>
> +1 for having /plan and /scan, sounds like a good idea to separate those 2
> distinct actions.
>
>
>
> Also +1 for having a more strict definition of the shard. Having arbitrary
> JSON was basically what we experimented with a string shard ID, and we
> ended up with something very similar to the manifest plan task you describe
> in the serialized ID string.
>
>
>
> So sounds like we are converging to the following APIs:
>
>
>
>
> *POST /v1/namespaces/ns/tables/t/plan *{ "filter": { "type": "in",
> "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"]}
>
> { "manifest-plan-tasks": [
> { "start": 0, "length": 1000, "manifest": { "path":
> "s3://some/manifest.avro", ...}, "delete-manifests": [...] },
> { ... }
> ]}
>
>
> *POST /v1/namespaces/ns/tables/t/scan *{ "filter": {"type": "in", "term":
> "x", "values": [1, 2, 3] },
>
> "select": ["x", "a.b"],
> "manifest-plan-task": { "start": 0, "length": 1000, "manifest": {
> "path": "s3://some/manifest.avro", ...}, "delete-manifests": [...] } }
>
> { "file-scan-tasks": [...] }
>
>
> *POST /v1/namespaces/ns/tables/t/scan *{ "filter": {"type": "in", "term":
> "x", "values": [1, 2, 3] }, "select": ["x", "a.b"]}
>
>
> { "file-scan-tasks": [...] }
>
>
>
> If this sounds good overall, we can update the prototype to have more
> detailed discussions in code.
>
>
>
> -Jack
>
>
>
>
>
>
>
>
>
>
>
> On Thu, Dec 14, 2023 at 6:10 PM Ryan Blue <b...@tabular.io> wrote:
>
> The tasks might look something like this:
>
>
>
> CombinedPlanTask
>
> - List<ManifestPlanTask>
>
>
>
> ManifestPlanTask
>
> - int start
>
> - int length
>
> - ManifestFile dataManifest
>
> - List<ManifestFile> deleteManifests
>
>
>
> On Thu, Dec 14, 2023 at 4:07 PM Ryan Blue <b...@tabular.io> wrote:
>
> Seems like that track has expired (This Internet-Draft will expire on 13
> May 2022)
>
> Yeah, looks like we should just use POST. That’s too bad. QUERY seems like
> a good idea to me.
>
> Distinguish planning using shard or not
>
> I think this was a mistake on my part. I was still thinking that we would
> have a different endpoint for first-level planning to produce shards and
> the route to actually get files. Since both are POST requests with the same
> path (/v1/namespaces/ns/tables/t/scans) that no longer works. What about
> /v1/namespaces/ns/tables/t/scan and /v1/namespaces/ns/tables/t/plan? The
> latter could use some variant of planFiles since that’s what we are
> wrapping in the Java API.
>
> Necessity of scan ID
>
> Yes, I agree. If you have shard IDs then you don’t really need a scan ID.
> You could always have one internally but send it as part of the shard ID.
>
> Shape of shard payload
>
> I think we have 2 general options depending on how strict we want to be.
>
> 1. Require a standard shard definition
> 2. Allow arbitrary JSON and leave it to the service
>
> I lean toward the first option, which would be a data manifest and the
> associated delete manifests for the partition. We could also extend that to
> a group of manifests, each with a list of delete manifests. And we could
> also allow splitting to ensure tasks don’t get too large with big files.
> This all looks basically like FileScanTask, but with manifests and delete
> manifests.
>
>
>
> On Wed, Dec 13, 2023 at 4:39 PM Jack Ye <yezhao...@gmail.com> wrote:
>
> Seems like that track has expired (This Internet-Draft will expire on 13
> May 2022), not sure how these RFCs are managed, but it does not seem
> hopeful to have this verb in. I think people are mostly using POST for this
> use case already.
>
>
>
> But overall I think we are in agreement with the general direction. A few
> detail discussions:
>
>
>
> *Distinguish planning using shard or not*
>
> Maybe we should add a query parameter like *distributed=true* to
> distinguish your first and third case, since they are now sharing the same
> signature. If the requester wants to use distributed planning, then some
> sharding strategy is provided as a response for the requester to send more
> detailed requests.
>
> *Necessity of scan ID*
> In this approach, is scan ID still required? Because the shard payload
> already fully describes the information to retrieve, it seems like we can
> just drop the *scan-id* query parameter in the second case. Seems like
> it's kept for the case if we still want to persist some state, but it seems
> like we can make a stateless style fully working.
>
> *Shape of shard payload*
> What do you think is necessary information of the shard payload? It seems
> like we need at least the location of the manifests, plus the delete
> manifests or delete files associated with the manifests. I like the idea of
> making it a "shard task" that is similar to a file scan task, and it might
> allow us to return a mixture of both types of tasks, so we can have better
> control of the response size.
>
> -Jack
>
>
>
> On Wed, Dec 13, 2023 at 3:50 PM Ryan Blue <b...@tabular.io> wrote:
>
> I just changed it to POST after looking into support for the QUERY method.
> It's a new HTTP method for cases like this where you don't want to pass
> everything through query params. Here's the QUERY method RFC
> <https://www.ietf.org/archive/id/draft-ietf-httpbis-safe-method-w-body-02.html>,
> but I guess it isn't finalized yet?
>
>
>
> Just read them like you would a POST request that doesn't actually create
> anything.
>
>
>
> On Wed, Dec 13, 2023 at 3:45 PM Jack Ye <yezhao...@gmail.com> wrote:
>
> Thanks, the Gist explains a lot of things. This is actually very close to
> our way of implementing the shard ID, we were defining the shard ID as a
> string, and the string content is actually something similar to the
> information of the JSON payload you showed, so we can persist minimum
> information in storage.
>
>
>
> Just one clarification needed for your Gist:
>
>
>
> > QUERY /v1/namespaces/ns/tables/t/scans?scan-id=1
>
>
>
> > { "shard": { "id": 1, "manifests": ["C"] }, "filter": {"type": "in",
> "term": "x", "values": [1, 2, 3] } }
>
>
>
> >
>
> > { "file-scan-tasks": [...] }
>
>
>
> Here, what does this QUERY verb mean? Is that a GET? If it's GET, we
> cannot have a request body. That's actually why we expressed that as an ID
> string, since we can put it as a query parameter.
>
>
>
> -Jack
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> On Wed, Dec 13, 2023 at 3:25 PM Ryan Blue <b...@tabular.io> wrote:
>
> Jack,
>
> It sounds like what I’m proposing isn’t quite clear because your initial
> response was arguing for a sharding capability. I agree that sharding is a
> good idea. I’m less confident about two points:
>
> 1. Requiring that the service is stateful. As Renjie pointed out, that
> makes it harder to scale the service.
> 2. The need for both pagination *and* sharding as separate things
>
> And I also think that Fokko has a good point about trying to keep things
> simple and not requiring the CreateScan endpoint.
>
> For the first point, I’m proposing that we still have a CreateScan
> endpoint, but instead of sending only a list of shard IDs it can also send
> either a standard shard “task” or an optional JSON definition. Let’s assume
> we can send arbitrary JSON for an example. Say I have a table with 4
> manifests, A through D and that C and D match some query filter. When I
> call the CreateScan endpoint, the service would send back tasks with that
> information: {"id": 1, "manifests": ["C"]}, {"id": 2, "manifests": ["D"]}.
> By sending what the shards mean (the manifests to read), my service can be
> stateless: any node can get a request for shard 1, read manifest C, and
> send back the resulting data files.
>
> I don’t see much of an argument against doing this *in principle*. It
> gives you the flexibility to store state if you choose or to send state to
> the client for it to pass back when calling the GetTasks endpoint. There
> is a practical problem, which is that it’s annoying to send a GET request
> with a JSON payload because you can’t send a request body. It’s probably
> obvious, but I’m also not a REST purist so I’d be fine using POST or QUERY
> for this. It would look something like this Gist
> <https://gist.github.com/rdblue/d2b65bd2ad20f85ee9d04ccf19ac8aba>.
>
> In your last reply, you also asked whether a stateless service is a goal.
> I don’t think that it is, but if we can make simple changes to the spec to
> allow more flexibility on the server side, I think that’s a good direction.
> You also asked about a reference implementation and I consider
> CatalogHandlers
> <https://github.com/apache/iceberg/blob/main/core/src/main/java/org/apache/iceberg/rest/CatalogHandlers.java>
> to be that reference. It does everything except for the work done by your
> choice of web application framework. It isn’t stateless, but it only relies
> on a Catalog implementation for persistence.
>
> For the second point, I don’t understand why we need both sharding and
> pagination. That is, if we have a protocol that allows sharding, why is
> pagination also needed? From my naive perspective on how sharding would
> work, we should be able to use metadata from the manifest list to limit the
> potential number of data files in a given shard. As long as we can limit
> the size of a shard to produce more, pagination seems like unnecessary
> complication.
>
> Lastly, for Fokko’s point, I think another easy extension to the proposal
> is to support a direct call to GetTasks. There’s a trade-off here, but if
> you’re already sending the original filter along with the request (in order
> to filter records from manifest C for instance) then the request is
> already something the protocol can express. There’s an objection concerning
> resource consumption on the service and creating responses that are too
> large or take too long, but we can get around that by responding with a
> code that instructs the client to use the CreateScan API like 413
> (Payload too large). I think that would allow simple clients to function
> for all but really large tables. The gist above also shows what this might
> look like.
>
> Ryan
>
>
>
> On Wed, Dec 13, 2023 at 11:53 AM Jack Ye <yezhao...@gmail.com> wrote:
>
> The current proposal definitely makes the server stateful. In our
> prototype we used other components like DynamoDB to keep track of states.
> If keeping it stateless is a tenant we can definitely make the proposal
> closer to that direction. Maybe one thing to make sure is, is this a core
> tenant of the REST spec? Today we do not even have an official reference
> implementation of the REST server, I feel it is hard to say what are the
> core tenants. Maybe we should create one?
>
>
>
> Pagination is a common issue in the REST spec. We also see similar
> limitations with other APIs like GetTables, GetNamespaces. When a catalog
> has many namespaces and tables it suffers from the same issue. It is also
> not ideal for use cases like web browsers, since typically you display a
> small page of results and do not need the full list immediately. So I feel
> we cannot really avoid some state to be kept for those use cases.
>
>
>
> Chunked response might be a good way to work around it. We also thought
> about using HTTP2. However, these options seem to be not very compatible
> with OpenAPI. We can do some further research in this domain, would really
> appreciate it if anyone has more insights and experience with OpenAPI that
> can provide some suggestions.
>
>
>
> -Jack
>
>
>
>
>
>
>
> On Tue, Dec 12, 2023 at 6:21 PM Renjie Liu <liurenjie2...@gmail.com>
> wrote:
>
> Hi, Rahi and Jack:
>
> Thanks for raising this.
>
>
>
> My question is that the pagination and sharding will make the rest server
> stateful, e.g. a sequence of calls is required to go to the same server. In
> this case, how do we ensure the scalability of the rest server?
>
>
>
>
>
> On Wed, Dec 13, 2023 at 4:09 AM Fokko Driesprong <fo...@apache.org> wrote:
>
> Hey Rahil and Jack,
>
>
>
> Thanks for bringing this up. Ryan and I also discussed this briefly in the
> early days of PyIceberg and it would have helped a lot in the speed of
> development. We went for the traditional approach because that would also
> support all the other catalogs, but now that the REST catalog is taking
> off, I think it still makes a lot of sense to get it in.
>
>
>
> I do share the concern raised Ryan around the concepts of shards and
> pagination. For PyIceberg (but also for Go, Rust, and DuckDB) that are
> living in a single process today the concept of shards doesn't add value. I
> see your concern with long-running jobs, but for the non-distributed cases,
> it will add additional complexity.
>
>
>
> Some suggestions that come to mind:
>
> - Stream the tasks directly back using a chunked response, reducing
> the latency to the first task. This would also solve things with the
> pagination. The only downside I can think of is having delete files where
> you first need to make sure there are deletes relevant to the task, this
> might increase latency to the first task.
> - Making the sharding optional. If you want to shard you call the
> CreateScan first and then call the GetScanTask with the IDs. If you don't
> want to shard, you omit the shard parameter and fetch the tasks directly
> (here we need also replace the scan string with the full
> column/expression/snapshot-id etc).
>
> Looking forward to discussing this tomorrow in the community sync
> <https://iceberg.apache.org/community/#iceberg-community-events>!
>
>
>
> Kind regards,
>
> Fokko
>
>
>
>
>
>
>
> Op ma 11 dec 2023 om 19:05 schreef Jack Ye <yezhao...@gmail.com>:
>
> Hi Ryan, thanks for the feedback!
>
>
>
> I was a part of this design discussion internally and can provide more
> details. One reason for separating the CreateScan operation was to make the
> API asynchronous and thus keep HTTP communications short. Consider the case
> where we only have GetScanTasks API, and there is no shard specified. It
> might take tens of seconds, or even minutes to read through all the
> manifest list and manifests before being able to return anything. This
> means the HTTP connection has to remain open during that period, which is
> not really a good practice in general (consider connection failure, load
> balancer and proxy load, etc.). And when we shift the API to asynchronous,
> it basically becomes something like the proposal, where a stateful ID is
> generated to be able to immediately return back to the client, and the
> client get results by referencing the ID. So in our current prototype
> implementation we are actually keeping this ID and the whole REST service
> is stateful.
>
>
>
> There were some thoughts we had about the possibility to define a "shard
> ID generator" protocol: basically the client agrees with the service a way
> to deterministically generate shard IDs, and service uses it to create
> shards. That sounds like what you are suggesting here, and it pushes the
> responsibility to the client side to determine the parallelism. But in some
> bad cases (e.g. there are many delete files and we need to read all those
> in each shard to apply filters), it seems like there might still be the
> long open connection issue above. What is your thought on that?
>
>
>
> -Jack
>
>
>
> On Sun, Dec 10, 2023 at 10:27 AM Ryan Blue <b...@tabular.io> wrote:
>
> Rahil, thanks for working on this. It has some really good ideas that we
> hadn't considered before like a way for the service to plan how to break up
> the work of scan planning. I really like that idea because it makes it much
> easier for the service to keep memory consumption low across requests.
>
>
>
> My primary feedback is that I think it's a little too complicated (with
> both sharding and pagination) and could be modified slightly so that the
> service doesn't need to be stateful. If the service isn't necessarily
> stateful then it should be easier to build implementations.
>
>
>
> To make it possible for the service to be stateless, I'm proposing that
> rather than creating shard IDs that are tracked by the service, the
> information for a shard can be sent to the client. My assumption here is
> that most implementations would create shards by reading the manifest list,
> filtering on partition ranges, and creating a shard for some reasonable
> size of manifest content. For example, if a table has 100MB of metadata in
> 25 manifests that are about 4 MB each, then it might create 9 shards with
> 1-4 manifests each. The service could send those shards to the client as a
> list of manifests to read and the client could send the shard information
> back to the service to get the data files in each shard (along with the
> original filter).
>
>
>
> There's a slight trade-off that the protocol needs to define how to break
> the work into shards. I'm interested in hearing if that would work with how
> you were planning on building the service on your end. Another option is to
> let the service send back arbitrary JSON that would get returned for each
> shard. Either way, I like that this would make it so the service doesn't
> need to persist anything. We could also make it so that small tables don't
> require multiple requests. For example, a client could call the route to
> get file tasks with just a filter.
>
>
>
> What do you think?
>
>
>
> Ryan
>
>
>
> On Fri, Dec 8, 2023 at 10:41 AM Chertara, Rahil
> <rcher...@amazon.com.invalid> wrote:
>
> Hi all,
>
> My name is Rahil Chertara, and I’m a part of the Iceberg team at Amazon
> EMR and Athena. I’m reaching out to share a proposal for a new Scan API
> that will be utilized by the RESTCatalog. The process for table scan
> planning is currently done within client engines such as Apache Spark. By
> moving scan functionality to the RESTCatalog, we can integrate Iceberg
> table scans with external services, which can lead to several benefits.
>
> For example, we can leverage caching and indexes on the server side to
> improve planning performance. Furthermore, by moving this scan logic to the
> RESTCatalog, non-JVM engines can integrate more easily. This all can be
> found in the detailed proposal below. Feel free to comment, and add your
> suggestions .
>
> Detailed proposal:
> https://docs.google.com/document/d/1FdjCnFZM1fNtgyb9-v9fU4FwOX4An-pqEwSaJe8RgUg/edit#heading=h.cftjlkb2wh4h
>
> Github POC: https://github.com/apache/iceberg/pull/9252
>
> Regards,
>
> Rahil Chertara
> Amazon EMR & Athena
> rcher...@amazon.com
>
>
>
>
>
>
> --
>
> Ryan Blue
>
> Tabular
>
>
>
>
> --
>
> Ryan Blue
>
> Tabular
>
>
>
>
> --
>
> Ryan Blue
>
> Tabular
>
>
>
>
> --
>
> Ryan Blue
>
> Tabular
>
>
>
>
> --
>
> Ryan Blue
>
> Tabular
>
>
>
>
> --
>
> Ryan Blue
>
> Tabular
>
>
>
>
> --
>
> Ryan Blue
>
> Tabular
>
>
>
>
> --
>
> Ryan Blue
>
> Tabular
>
